import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        StringBuffer sb = new StringBuffer();
        char[] arr = str.toCharArray();
        for (int i = 0; i < str.length() - 1; i++) {

            if (!Character.isDigit(arr[i]) && Character.isDigit(arr[i + 1])) {
                sb.append(" ");
            }

            if (Character.isDigit(arr[i])) {
                sb.append(arr[i]);
            }
        }
        if(Character.isDigit(str.charAt(str.length()-1))) {
            sb.append(str.charAt(str.length()-1));
        }
        if(sb.charAt(0) == ' ') {
            sb = sb.replace(0, 1, "");
        }
        // System.out.println("sb:" + sb);

        String[] strs =  sb.toString().split(" ");
        int tmp = 0;
        for (int i = 0; i < strs.length-1; i++) {
            if(strs[tmp].length() < strs[i+1].length()) {
                tmp = i+1;
            }
        }
        System.out.println(strs[tmp]);
    }

}